bascule de visibilité Search & Display Options

Tout Sélectionner    Désélectionner
 |   | 
Détails
   print
  Enregistrements Liens
Auteur Darnaude, A.M.; Sturrock, A.; Trueman, C.N.; Mouillot, D.; Eimf; Campana, S.E.; Hunter, E. url  doi
openurl 
  Titre Listening In on the Past: What Can Otolith δ18O Values Really Tell Us about the Environmental History of Fishes? Type Article scientifique
  Année 2014 Publication Revue Abrégée PLoS ONE  
  Volume 9 Numéro 10 Pages  
  Mots-Clés  
  Résumé Oxygen isotope ratios from fish otoliths are used to discriminate marine stocks and reconstruct past climate, assuming that variations in otolith δ18O values closely reflect differences in temperature history of fish when accounting for salinity induced variability in water δ18O. To investigate this, we exploited the environmental and migratory data gathered from a decade using archival tags to study the behaviour of adult plaice (Pleuronectes platessa L.) in the North Sea. Based on the tag-derived monthly distributions of the fish and corresponding temperature and salinity estimates modelled across three consecutive years, we first predicted annual otolith δ18O values for three geographically discrete offshore sub-stocks, using three alternative plausible scenarios for otolith growth. Comparison of predicted vs. measured annual δ18O values demonstrated >96% correct prediction of sub-stock membership, irrespective of the otolith growth scenario. Pronounced inter-stock differences in δ18O values, notably in summer, provide a robust marker for reconstructing broad-scale plaice distribution in the North Sea. However, although largely congruent, measured and predicted annual δ18O values of did not fully match. Small, but consistent, offsets were also observed between individual high-resolution otolith δ18O values measured during tag recording time and corresponding δ18O predictions using concomitant tag-recorded temperatures and location-specific salinity estimates. The nature of the shifts differed among sub-stocks, suggesting specific vital effects linked to variation in physiological response to temperature. Therefore, although otolith δ18O in free-ranging fish largely reflects environmental temperature and salinity, we counsel prudence when interpreting otolith δ18O data for stock discrimination or temperature reconstruction until the mechanisms underpinning otolith δ18O signature acquisition, and associated variation, are clarified.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection (down) 1195  
Lien permanent pour cet enregistrement
 

 
Auteur Benazzouz, A.; Pelegri, J.L.; Demarcq, H.; Machin, F.; Mason, E.; Orbi, A.; Pena-Izquierdo, J.; Soumia, M. url  doi
openurl 
  Titre On the temporal memory of coastal upwelling off NW Africa Type Article scientifique
  Année 2014 Publication Revue Abrégée J. Geophys. Res.-Oceans  
  Volume 119 Numéro 9 Pages 6356-6380  
  Mots-Clés atlantic; Canary Current; cape blanc region; circulation; Coastal upwelling; eastern boundary; Ekman transport; interannual variability; northwest africa; NW Africa; sea-surface temperature; SST difference; system; temporal memory; water  
  Résumé We use a combination of satellite, in situ, and numerical data to provide a comprehensive view of the seasonal coastal upwelling cycle off NW Africa in terms of both wind forcing and sea surface temperature (SST) response. Wind forcing is expressed in terms of both instantaneous (local) and time-integrated (nonlocal) indices, and the ocean response is expressed as the SST difference between coastal and offshore waters. The classical local index, the cross-shore Ekman transport, reproduces reasonably well the time-latitude distribution of SST differences but with significant time lags at latitudes higher than Cape Blanc. Two nonlocal indices are examined. One of them, a cumulative index calculated as the backward averaged Ekman transport that provides the highest correlation with SST differences, reproduces well the timing of the SST differences at all latitudes (except near Cape Blanc). The corresponding time lags are close to zero south of Cape Blanc and range between 2 and 4 months at latitudes between Cape Blanc and the southern Gulf of Cadiz. The results are interpreted based on calculations of spatial and temporal auto and cross correlations for wind forcing and SST differences. At temporal scales of 2-3 weeks, the alongshore advection of alongshore momentum compensates for interfacial friction, allowing the upwelling jet and associated frontal system to remain active. We conclude that the coastal jet plays a key role in maintaining the structure of coastal upwelling, even at times of relaxed winds, by introducing a seasonal memory to the system in accordance with the atmospheric-forcing annual cycle.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 2169-9275 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection (down) 1194  
Lien permanent pour cet enregistrement
 

 
Auteur Zilius, M.; Bartoli, M.; Bresciani, M.; Katarzyte, M.; Ruginis, T.; Petkuviene, J.; Lubiene, I.; Giardino, C.; Bukaveckas, P.A.; De Wit, R.; Razinkovas-Baziukas, A. url  doi
openurl 
  Titre Feedback Mechanisms Between Cyanobacterial Blooms, Transient Hypoxia, and Benthic Phosphorus Regeneration in Shallow Coastal Environments Type Article scientifique
  Année 2014 Publication Revue Abrégée Estuaries and Coasts  
  Volume 37 Numéro 3 Pages 680-694  
  Mots-Clés baltic sea; chesapeake bay; curonian lagoon; Cyanobacterial blooms; ecosystem metabolism; Estuary; gulf; Hypoxia; Net; nutrient limitation; Oxygen; Phosphorus release; respiration; satellite data; temporal variability  
  Résumé We investigated the dissolved oxygen metabolism of the Curonian Lagoon (Baltic Sea) to assess the relative contributions of pelagic and benthic processes to the development of transient hypoxic conditions in shallow water habitats. Metabolism measurements along with the remote sensing-derived estimates of spatial variability in chlorophyll a were used to evaluate the risk of hypoxia at the whole lagoon level. Our data demonstrate that cyanobacterial blooms strongly inhibit light penetration, resulting in net heterotrophic conditions in which pelagic oxygen demand exceeds benthic oxygen demand by an order of magnitude. The combination of bloom conditions and reduced vertical mixing during calm periods resulted in oxygen depletion of bottom waters and greater sediment nutrient release. The peak of reactive P regeneration (nearly 30 mu mol m(-2) h(-1)) coincided with oxygen depletion in the water column, and resulted in a marked drop of the inorganic N:P ratio (from > 40 to < 5, as molar). Our results suggest a strong link between cyanobacterial blooms, pelagic respiration, hypoxia, and P regeneration, which acts as a feedback in sustaining algal blooms through internal nutrient cycling. Meteorological data and satellite-derived maps of chlorophyll a were used to show that nearly 70 % of the lagoon surface (approximately 1,000 km(2)) is prone to transient hypoxia development when blooms coincide with low wind speed conditions.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 1559-2723 ISBN Médium  
  Région Expédition Conférence  
  Notes <p>ISI Document Delivery No.: AF0SM<br/>Times Cited: 1<br/>Cited Reference Count: 66<br/>Zilius, Mindaugas Bartoli, Marco Bresciani, Mariano Katarzyte, Marija Ruginis, Tomas Petkuviene, Jolita Lubiene, Irma Giardino, Claudia Bukaveckas, Paul A. de Wit, Rutger Razinkovas-Baziukas, Arturas<br/>European Union Structural Funds project “Postdoctoral Fellowship Implementation in Lithuania”; Fulbright Fellowship; ESA project [AO-553]; CYAN-IS-WAS (Ministero dell'Istruzione dell'Universita e della Ricerca, Science and technological of Sweden); CLAM-PHYM (Italian Space Agency) [ASI I/015/11/0]<br/>Mindaugas Zilius was supported by a postdoctoral fellowship funded by the European Union Structural Funds project “Postdoctoral Fellowship Implementation in Lithuania.” Paul Bukaveckas was supported by a Fulbright Fellowship during his residence at Klaipeda University. MERIS data were made available through the ESA project AO-553 (MELINOS). This study was co-funded by CYAN-IS-WAS (Ministero dell'Istruzione dell'Universita e della Ricerca, Science and technological cooperation between Italy and the Kingdom of Sweden) and CLAM-PHYM (Italian Space Agency, contract ASI I/015/11/0) projects. We gratefully thank the Lithuanian Hydrometeorological Service of the Ministry of Environment for providing meteorological data. We also gratefully thank three anonymous reviewers for valuable comments which improved the quality of the manuscript.<br/>Springer<br/>New york</p> Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection (down) 1184  
Lien permanent pour cet enregistrement
 

 
Auteur Zhao, T.; Villeger, S.; Lek, S.; Cucherousset, J. url  doi
openurl 
  Titre High intraspecific variability in the functional niche of a predator is associated with ontogenetic shift and individual specialization Type Article scientifique
  Année 2014 Publication Revue Abrégée Ecology and Evolution  
  Volume 4 Numéro 24 Pages 4649-4657  
  Mots-Clés functional traits; niche; ontogeny; overlap; stable isotope analyses  
  Résumé Investigations on the functional niche of organisms have primarily focused on differences among species and tended to neglect the potential effects of intraspecific variability despite the fact that its potential ecological and evolutionary importance is now widely recognized. In this study, we measured the distribution of functional traits in an entire population of largemouth bass (Micropterus salmoides) to quantify the magnitude of intraspecific variability in functional traits and niche (size, position, and overlap) between age classes. Stable isotope analyses (δ13C and δ15N) were also used to determine the association between individual trophic ecology and intraspecific functional trait variability. We observed that functional traits were highly variable within the population (mean coefficient variation: 15.62% ± 1.78% SE) and predominantly different between age classes. In addition, functional and trophic niche overlap between age classes was extremely low. Differences in functional niche between age classes were associated with strong changes in trophic niche occurring during ontogeny while, within age classes, differences among individuals were likely driven by trophic specialization. Each age class filled only a small portion of the total functional niche of the population and age classes occupied distinct portions in the functional space, indicating the existence of ontogenetic specialists with different functional roles within the population. The high amplitude of intraspecific variability in functional traits and differences in functional niche position among individuals reported here supports the recent claims for an individual-based approach in functional ecology.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 2045-7758 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection (down) 1183  
Lien permanent pour cet enregistrement
 

 
Auteur Wang, T.; Lefevre, S.; Iversen, N.K.; Findorf, I.; Buchanan, R.; McKenzie, D.J. url  doi
openurl 
  Titre Anaemia only causes a small reduction in the upper critical temperature of sea bass: is oxygen delivery the limiting factor for tolerance of acute warming in fishes? Type Article scientifique
  Année 2014 Publication Revue Abrégée Journal of Experimental Biology  
  Volume 217 Numéro 24 Pages 4275-4278  
  Mots-Clés aerobic scope; cardiac-performance; Cardiovascular; climate-change; dicentrarchus-labrax; ecology; exp. biol. 216; fish; Haematocrit; metabolism; Oxygen transport; phenylhydrazine-induced anemia; thermal tolerance; trout  
  Résumé To address how the capacity for oxygen transport influences tolerance of acute warming in fishes, we investigated whether a reduction in haematocrit, by means of intra-peritoneal injection of the haemolytic agent phenylhydrazine, lowered the upper critical temperature of sea bass. A reduction in haematocrit from 42 +/- 2% to 20 +/- 3% (mean +/- s.e.m.) caused a significant but minor reduction in upper critical temperature, from 35.8 +/- 0.1 to 35.1 +/- 0.2 degrees C, with no correlation between individual values for haematocrit and upper thermal limit. Anaemia did not influence the rise in oxygen uptake between 25 and 33 degrees C, because the anaemic fish were able to compensate for reduced blood oxygen carrying capacity with a significant increase in cardiac output. Therefore, in sea bass the upper critical temperature, at which they lost equilibrium, was not determined by an inability of the cardio-respiratory system to meet the thermal acceleration of metabolic demands.  
  Adresse  
  Auteur institutionnel Thèse  
  Editeur Lieu de Publication Éditeur  
  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0022-0949 ISBN Médium  
  Région Expédition Conférence  
  Notes <p>ISI Document Delivery No.: AW7BT<br/>Times Cited: 1<br/>Cited Reference Count: 44<br/>Wang, Tobias Lefevre, Sjannie Iversen, Nina K. Findorf, Inge Buchanan, Rasmus McKenzie, David J.<br/>Centre National de la Recherche Scientifique (CNRS); Danish Research Council; Region Languedoc-Roussillon (RLR); Ambassade de France in Copenhagen; Universite Montpellier 2<br/>This research was supported by the Centre National de la Recherche Scientifique (CNRS), the Danish Research Council, The Ambassade de France in Copenhagen and Universite Montpellier 2. T.W. was supported by a fellowship from Region Languedoc-Roussillon (RLR) as a visiting professor at Universite Montpellier 2. I.F. and N.K.I. were supported by a student grant from The Ambassade de France in Copenhagen.<br/>Company of biologists ltd<br/>Cambridge</p> Approuvé pas de  
  Numéro d'Appel MARBEC @ alain.herve @ collection (down) 1181  
Lien permanent pour cet enregistrement
Tout Sélectionner    Désélectionner
 |   | 
Détails
   print

Save Citations:
Export Records: